The surface membrane properties of murine BALB/c 3T3, SV40-transformed 3T3, and revertant variant cells of SV40-transformed 3T3 which have regained density-dependent inhibition of growth are being examined. Attention has been focused on the substrate-attached material (SAM), which are the adhesion sites which pinch off from the rest of the cell surface and which remain bound to the tissue culture substrate subsequent to EGTA-mediated detachment of cells. Since SAM is greatly enriched in glycosaminoglycans (GAG), we are interested in determining the molecular organization and the prospective function of these GAG's and their proteoglycans in this adhesive material. The organization of these proteoglycans will be explored in "footpad" adhesion site and in "footprints", which are adhesion sites pinched off from the posterior of the cell as it moves across the substratum. Various molecular probes will be used to determine the topographical organization of GAG's and their proteoglycans in these sites. We are particularly interested in determining whether they exist as "supramolecular" complexes comparable to those found in cartilaginous tissues. The mechanism of cellular adhesion to serum-absorbed substrates will also be probed by studying a variety of adhesive parameters in the presence or absence of exogenously-added GAG's and/or proteoglycans. These studies will hopefully elucidate the functional role which GAG's and their proteoglycans play in one type of cellualr adhesion process and whether this role is different for normal and malignant cells.